Mobile computer devices such as a PDA (Personal Digital Assistance) and small portable telecommunication devices including a cellular phone and a PCS (Personal Communication System) have been widely used with the developments of wireless telecommunication technology and computer device technology. By storing information in the devices, information can be easily and conveniently managed, and enormous information can also be transferred to the user by the wireless internet connections.
However, the size of display screen of the mobile computer device is not large enough to display sufficient information stored in the memory of the devices or transferred from the internet connection, and only a part of information can be displayed on the monitor of the device. Therefore, users generally move the display screen by pressing the arrow keys equipped on the devices or by using a separate mouse connected to the device to see the entire information. However, it is not easy to install at least four arrow keys on the small mobile devices to move the display screen, and furthermore handling of such keys is cumbersome and not convenient for users.